Friday, May 29, 2009


Triiodothyronine, with the chemical structure of 3,5,3'-L-triiodothyronine, well known as T3 because of it's difficulty to pronounce is one of the main Thyroid Hormone produced from the Thyroid gland and controlled by the TSH form the anterior pituitary gland. T4 with T3 are the most important hormone that affects metabolic rates. they help regulates the metabolic processes which are essential for a normal growth and development of our body and the maturation of our brain cells.
t3 is 3 to 5 times more potent biological system thab t4 because one third of all t4 are converted to t3 during the course of it's metabolism.


  • increased oxygen consumption

  • growth

  • development

  • sexual maturation

  • stimulation of heart rate and heart contraction

  • protein synthesis

  • carbohydrate metabolism

  • cholesterol and TAG synthesis and degradation

IDEAL SPECIMEN: serum; plasma with EDTA or heparin may also be used


  • Direct Equilibrium Dialysis or Infiltration

  • Determination of T3 by Radioimmunoassay (T3(RIA)

  • Determination of T3 Uptake by Radioassay

Normal Values: 0.8 - 1.1 ug/dL

Clinical Significance:

  • Primary Hypothyroidism - has damage in the thyroid gland and insufficient in hormone synthesis. Confirmation of the disease is the results where T3 and T4 decrease; TSH increase.

  • Congenital Hypothyroidism - due to absence of thyroid gland or defects on thyroid hormone synthesis.

  • Secondary Hypothyroidism - due to pitiutary or hypothalamic disease;
  • Hyperthyroidism - can be caused by diffused toxic goiter, damage to the thyroid gland. T3 is elevated early than T4.


Tietz Textbook of Clinical Chemistry Second Edition by Karl A. Burtis and Edward R. Ashwood

Fundamentals of Clinical Chemistry Third Edition by Norbert W. Tietz


  1. Hi Kelly,

    Start writing your content.

  2. This comment has been removed by the author.

  3. good post kelly, but whats the picture got to do with your post? just curious..haha

  4. Good points:

    1. Cool color.

    1. Discuss methods in your next post.
    2. Change Blog title to Clinical Chemistry Blog Notes 16
    3. Use correct titles in blog roll.
    4. Include relevant pics in post with the links to the actual site.
    5. Include hyperlinks to relevant topics.

  5. the girl in the post represents growth which is one of the functions of t3.

  6. Nicely done! I would read through this post because this is concise, informative, well spaced, the color and theme were both appealing.

    A little more fine tuning on the content and some links would be great. Since this is in a formal context, you may want to correct some typos.

    Overall: This is a promising blog. Keep it up!

    I hope you'd follow your teacher's advise too.


  7. Great job!
    Your post is nice, well summarized, informative and easy to understand.
    Thanks for the information.
    keep it up...=)

  8. Great post, keep it up!. Learnning is not just inside of the classrooms but also sharing the knowledge we've learned with other,,.

  9. oh, i got the picture! good thinking kelly. haha

  10. nice job,
    but can you explain on what are the principles
    of the methods in determining T3?
    but over all nice post, and the explanation of the C.S.

  11. i like how you discussed your topic.. its well explained and you made it easy to understand..
    pls put related photos..

  12. the girl in the post represents growth which is one of the functions of t3. makulit n kretel. hahaha..